Motor fuel



Patented Sept. 27, 2

* UNITED. STATES-PATENT; OFFICE" Josmm o. navmson," or Yomns, Raw 1031:, nssr'enon 'ro cnnnnm & cannon conroaxnon, a

oonromvrron or-New You Moron. run.

Io Drawing.

' press the mixture of fuel and air before igniting it.

In an application filed January 6, 1928,

- Serial No. 245,057, I have described and claimed non-detonating fuel blends comprising paraflin hydrocarbon material, for example petroleum distillates, and plural carbon atom side chain alkyl benzenes, such as the ethyl and isopropyl benzenes'. As there explained, oneor more of the six h drogen atoms of the benzene nucleus can be replaced by plural carbon atom alkyl groups, and the groups so substituted in a-single molecule may be identical or different. The blends proposed in my prior application contain a substantial quantity of an alkyl benzene of which the molecule contains at least one pluralcarbon-atom side-chain.

The present invention contemplates the blending of an alkyl benzene containing a plural-carbon-atom side-chain and a paraffine hydrocarbon liquid having a distillation end-point not above about 330 F. The paratfine hydrocarbon liquid used is preferably a material of the type known to the gasoline industry as natural gasoline, natural gas gasoline, or casing-head gasoline.

Natural gasolines, as a rule, show but little tendency to detonate in internal combustion engines. This is partially due to the low average molecular weight of the compounds present, but it also seems to be a fact that where isomeric compounds (e. g. octanes) are 7 involved, the isomers which are principally j present in natural gasoline have alower tendv 40 -ency to detonate than the isomers principally present in petroleum gasoline.

'Natural gasolines are not well adapted to be used as motor fuel without blending with les volatile liquids. Unblended, they evaporate excessively in storage, and when used in aeronautical motors the craft may climb so rapidly that the barometric pressure falls below the vapor pressure of the fuel, whereupon the latter boils in the fuel tanks, giving rise to operating difiiculties. If, to overcome these Application ma December :7, mm. mm in. 328,856.

defects, the natural gasoline is blended with less volatile parafline hydrocarbon distillates, the tendency to detonate is increased, and lower compressions must be used. Natural gasoline may be blended with plural carbon atom side chain alkyl benzene material to produce a fuel which is not volatile, which properly combines constituents of various oiling points, and which may be used at very high compressions Without detonation.

Natural gasolines may be combined with the plural carbon atom side chain alkyl benzenes in various proportions, according to the type of boiling curve desired, and the choice of the alkyl benzene used may be controlled by the same consideration. I prefer to use mixtures of the alkyl benzene to obtain smoother boiling curves, and because mixtures can be produced more cheaply than the pure compounds. The boiling points of typical plural carbon side chain alkyl benzenes are approximately as follows:

F. Monoethyl benzene 274 Monoisopropyl benzene 304 Monopropyli benzene; 315 Monobutyl benzene 362 In the series of compounds containing from one to sixethylgroups, the boiling point increases withr the degree of alkylation, and so with the isopropyl and higher alkyl benzenes. By way of illustrating the inven tion, I refer to ablen'd'containing of natural gasoline and20% 'oifa 'mixture of ethyl benzenes consisting.principally of the monoethyl compound, "-Thegasolineconformed to the following specifications-when distilled by the Associationfof"Natural Gasoline Manufacturers method Y erties of the blend, and the scope of t a fuel in accordance with the invention, there are available two series of chemical compounds, the boiling points of the plural carbon atom side chain alkyl benzenes increasing by small increments from about 274 F.,

and the boiling points of the'parafiinjhydro- 5 gasoline diminishing carbons in the natural by small increments from a figure in' the vicinity of 330 F. All of the compounds are characteristically non-detonating, so that a non-detonatingblend of any desired boiling curve and distillation end-point can'be readily prepared. Other substances, for example other hydrocarbons, or compounds which act to suppress detonation, can of course be incorporated in appropriate quantities Without destroying the desirable Iprope mvention is not to be limited except by the terms of the appended claims.

I claim 1. A motor fuel consisting of a blend of casing head gasoline having a distillation end-point not higher than about 330 F. and

' another liquid acting to diminish spontaneous evaporation thereof Without substantially raising the distillation end-point or increasing detonation, said other liquid consisting essentially of plural-carbon-atom side chain alkyl benzenes.

2. A motor fuel consisting of a blend of natural gas gasoline having a distillation end-point not higher than about 330 F. with an agent acting to diminish spontaneous evaporation thereof Without substantially raising the distillation end-point or increasing detonation, said agent comprising about 20% of the whole fuel and consisting substantially of ethyl benzenes.

In testimony whereof, I aflix my signature.

JOSEPH G. DAVIDSON. 

